Well is the first time i hear about tesla being murdered, who makes such a claims spread this rumours?
TPTB do not needed to kill tesla he was already discredited in his last years
for the tesla papers some about that history can be found at the fbi page.
https://vault.fbi.gov/nikola-tesla
worth the reading at fbis page :)
i do like the image that you choose here, i have it stored next to others of him.. did you know this photo was one of the first photos to be edited?. it is two photos, one with the rays , and one separatedly with tesla on the chair. was combined to make this type of "post card"